CoCrFeNiM高熵合金的制備、結(jié)構(gòu)及性能研究

CoCrFeNiM高熵合金的制備、結(jié)構(gòu)及性能研究一、本文概述Overviewofthisarticle隨著材料科學(xué)的快速發(fā)展，高熵合金作為一種新型的多主元合金，以其獨特的性能和設(shè)計理念，引起了廣泛的關(guān)注。其中，CoCrFeNiM高熵合金作為其中的一種，因其優(yōu)異的力學(xué)性能、抗腐蝕性和高溫穩(wěn)定性，在航空航天、能源、汽車等領(lǐng)域具有巨大的應(yīng)用潛力。本文旨在全面系統(tǒng)地研究CoCrFeNiM高熵合金的制備方法、微觀結(jié)構(gòu)及其相關(guān)性能，以期為其在工業(yè)應(yīng)用中的進一步推廣提供理論基礎(chǔ)和技術(shù)支持。Withtherapiddevelopmentofmaterialsscience,highentropyalloys,asanewtypeofmultiprincipalcomponentalloy,haveattractedwidespreadattentionduetotheiruniquepropertiesanddesignconcepts.Amongthem,CoCrFeNiMhighentropyalloy,asoneofthem,hasenormousapplicationpotentialinaerospace,energy,automotiveandotherfieldsduetoitsexcellentmechanicalproperties,corrosionresistance,andhigh-temperaturestability.Thisarticleaimstocomprehensivelyandsystematicallystudythepreparationmethods,microstructure,andrelatedpropertiesofCoCrFeNiMhighentropyalloys,inordertoprovidetheoreticalbasisandtechnicalsupportfortheirfurtherpromotioninindustrialapplications.本文首先將對高熵合金的概念、發(fā)展歷程和應(yīng)用前景進行簡要介紹，重點闡述CoCrFeNiM高熵合金的研究現(xiàn)狀和意義。隨后，將詳細介紹CoCrFeNiM高熵合金的制備方法，包括熔煉、鑄造、熱處理等工藝過程，并分析不同制備工藝對合金組織結(jié)構(gòu)和性能的影響。在此基礎(chǔ)上，通過先進的材料表征手段，如射線衍射、掃描電子顯微鏡、透射電子顯微鏡等，對CoCrFeNiM高熵合金的微觀結(jié)構(gòu)進行深入探究，揭示其獨特的原子排布和相結(jié)構(gòu)特征。Thisarticlewillfirstbrieflyintroducetheconcept,developmenthistory,andapplicationprospectsofhighentropyalloys,withafocusontheresearchstatusandsignificanceofCoCrFeNiMhighentropyalloys.Subsequently,adetailedintroductionwillbegiventothepreparationmethodsofCoCrFeNiMhighentropyalloys,includingprocessessuchasmelting,casting,andheattreatment,andtheeffectsofdifferentpreparationprocessesonthealloy'smicrostructureandpropertieswillbeanalyzed.Onthisbasis,advancedmaterialcharacterizationmethodssuchasX-raydiffraction,scanningelectronmicroscopy,transmissionelectronmicroscopy,etc.wereusedtodeeplyexplorethemicrostructureofCoCrFeNiMhighentropyalloy,revealingitsuniqueatomicarrangementandphasestructurecharacteristics.本文還將對CoCrFeNiM高熵合金的力學(xué)性能、電學(xué)性能、熱學(xué)性能以及抗腐蝕性等進行全面評價。通過拉伸試驗、硬度測試、電化學(xué)腐蝕試驗等手段，系統(tǒng)地分析合金的性能表現(xiàn)，探討其性能優(yōu)化的途徑和機理。本文將對CoCrFeNiM高熵合金的應(yīng)用前景進行展望，提出未來研究方向和建議，以期推動高熵合金領(lǐng)域的持續(xù)發(fā)展。Thisarticlewillalsocomprehensivelyevaluatethemechanicalproperties,electricalproperties,thermalproperties,andcorrosionresistanceofCoCrFeNiMhighentropyalloys.Bymeansoftensiletesting,hardnesstesting,electrochemicalcorrosiontesting,etc.,theperformanceofalloysissystematicallyanalyzed,andthewaysandmechanismsforoptimizingtheirperformanceareexplored.ThisarticlewillprovideanoutlookontheapplicationprospectsofCoCrFeNiMhighentropyalloys,proposefutureresearchdirectionsandsuggestions,inordertopromotethesustainabledevelopmentofthehighentropyalloyfield.二、CoCrFeNiM高熵合金的制備PreparationofCoCrFeNiMhighentropyalloy高熵合金（High-EntropyAlloys，簡稱HEAs）作為一種新型的合金設(shè)計概念，自提出以來就引起了廣泛的關(guān)注。CoCrFeNiM高熵合金作為其中的一種，因其獨特的成分設(shè)計和優(yōu)異的性能表現(xiàn)，成為了研究的熱點。本章節(jié)將詳細介紹CoCrFeNiM高熵合金的制備方法。Highentropyalloys(HEAs),asanewtypeofalloydesignconcept,haveattractedwidespreadattentionsincetheirinception.CoCrFeNiMhighentropyalloy,asoneofthem,hasbecomearesearchhotspotduetoitsuniquecompositiondesignandexcellentperformance.ThischapterwillprovideadetailedintroductiontothepreparationmethodsofCoCrFeNiMhighentropyalloys.制備CoCrFeNiM高熵合金的首要步驟是選擇合適的原料。本實驗選用高純度的Co、Cr、Fe、Ni和M（M為微量元素，具體選擇根據(jù)實驗需求而定）金屬粉末作為原料。這些金屬粉末的純度均達到9%以上，以確保最終合金的成分均勻性和性能穩(wěn)定性。TheprimarystepinpreparingCoCrFeNiMhighentropyalloysistoselectsuitablerawmaterials.Thisexperimentuseshigh-purityCo,Cr,Fe,Ni,andM(Misatraceelement,specificselectiondependsonexperimentalrequirements)metalpowdersasrawmaterials.Thepurityofthesemetalpowdersreachesover9%toensuretheuniformityofthefinalalloycompositionandperformancestability.按照CoCrFeNiM高熵合金的成分配比，精確稱量各金屬粉末，并進行混合?；旌线^程中，采用高能球磨機進行機械合金化，使各元素充分均勻分布。球磨過程中，球磨介質(zhì)的選擇、球磨時間以及球磨速度等參數(shù)都經(jīng)過精心設(shè)計和優(yōu)化，以確保合金成分的均勻性。AccordingtothecompositionratioofCoCrFeNiMhighentropyalloy,accuratelyweigheachmetalpowderandmixit.Duringthemixingprocess,ahigh-energyballmillisusedformechanicalalloyingtoensurethatallelementsarefullyanduniformlydistributed.Duringtheballmillingprocess,theselectionofmillingmedium,millingtime,andmillingspeedarecarefullydesignedandoptimizedtoensuretheuniformityofalloycomposition.混合均勻后的粉末通過壓制成型，得到所需的合金坯料。成型過程中，需要控制壓制壓力和保壓時間，以確保坯料的密度和形狀。隨后，將坯料進行真空燒結(jié)，以消除內(nèi)部孔隙和雜質(zhì)，提高合金的致密性和力學(xué)性能。燒結(jié)過程中，溫度、時間和氣氛等參數(shù)都經(jīng)過嚴格控制，以確保合金的燒結(jié)質(zhì)量。Themixedpowderisformedbypressingtoobtaintherequiredalloybillet.Duringtheformingprocess,itisnecessarytocontrolthepressingpressureandholdingtimetoensurethedensityandshapeofthebillet.Subsequently,thebilletisvacuumsinteredtoeliminateinternalporesandimpurities,improvingthedensityandmechanicalpropertiesofthealloy.Duringthesinteringprocess,parameterssuchastemperature,time,andatmospherearestrictlycontrolledtoensurethesinteringqualityofthealloy.燒結(jié)后的合金需要進行后處理，如熱處理、機械加工等，以滿足實際應(yīng)用的需求。對合金進行表征，如射線衍射（RD）、掃描電子顯微鏡（SEM）、能譜分析（EDS）等，以揭示其微觀結(jié)構(gòu)和元素分布。通過這些表征手段，可以評估合金的成分均勻性、晶體結(jié)構(gòu)、相組成以及微觀組織形貌等信息。Thesinteredalloyneedstoundergopost-treatment,suchasheattreatment,mechanicalprocessing,etc.,tomeettheneedsofpracticalapplications.Characterizethealloy,suchasX-raydiffraction(RD),scanningelectronmicroscopy(SEM),energydispersivespectroscopy(EDS),etc.,torevealitsmicrostructureandelementdistribution.Throughthesecharacterizationmethods,theuniformityofalloycomposition,crystalstructure,phasecomposition,andmicrostructuremorphologycanbeevaluated.CoCrFeNiM高熵合金的制備過程涉及原料選擇、配料與混合、成型與燒結(jié)以及后處理與表征等多個步驟。每個步驟都需要精細控制和優(yōu)化，以確保最終合金的成分均勻性、組織結(jié)構(gòu)和性能表現(xiàn)。通過本章節(jié)的介紹，讀者可以對CoCrFeNiM高熵合金的制備方法有一個全面而深入的了解。ThepreparationprocessofCoCrFeNiMhighentropyalloyinvolvesmultiplesteps,includingrawmaterialselection,ingredientandmixing,formingandsintering,aswellaspost-treatmentandcharacterization.Eachsteprequiresprecisecontrolandoptimizationtoensurethecompositionuniformity,microstructure,andperformanceofthefinalalloy.Throughtheintroductionofthischapter,readerscanhaveacomprehensiveandin-depthunderstandingofthepreparationmethodsofCoCrFeNiMhighentropyalloys.三、CoCrFeNiM高熵合金的結(jié)構(gòu)StructureofCoCrFeNiMHighEntropyAlloyCoCrFeNiM高熵合金的結(jié)構(gòu)是其優(yōu)異性能的基礎(chǔ)。通過先進的材料表征技術(shù)，我們對這種合金的微觀結(jié)構(gòu)進行了深入的研究。ThestructureofCoCrFeNiMhighentropyalloyisthebasisforitsexcellentperformance.Throughadvancedmaterialcharacterizationtechniques,wehaveconductedin-depthresearchonthemicrostructureofthisalloy.CoCrFeNiM高熵合金表現(xiàn)出典型的面心立方（FCC）結(jié)構(gòu)。這種結(jié)構(gòu)在多種高熵合金中都很常見，因其能夠提供良好的塑性變形能力和較高的強度。通過射線衍射（RD）分析，我們確認了合金的晶體結(jié)構(gòu)，并進一步通過Rietveld精修得到了晶格常數(shù)的精確值。晶格常數(shù)的變化反映了合金元素間相互作用的影響，對于理解合金的力學(xué)性能和熱學(xué)性能具有重要意義。CoCrFeNiMhighentropyalloysexhibitatypicalfacecenteredcubic(FCC)structure.Thisstructureiscommoninvarioushighentropyalloysbecauseitcanprovidegoodplasticdeformationabilityandhighstrength.ThroughX-raydiffraction(RD)analysis,weconfirmedthecrystalstructureofthealloyandfurtherobtainedtheprecisevalueoflatticeconstantthroughRietveldrefinement.Thechangeinlatticeconstantreflectstheinfluenceoftheinteractionbetweenalloyelements,whichisofgreatsignificanceforunderstandingthemechanicalandthermalpropertiesofalloys.除了晶體結(jié)構(gòu)外，我們還通過掃描電子顯微鏡（SEM）和透射電子顯微鏡（TEM）等手段，對CoCrFeNiM高熵合金的相組成和微觀組織進行了詳細的觀察。結(jié)果顯示，合金主要由單一FCC相組成，沒有觀察到明顯的第二相析出。這種單相結(jié)構(gòu)有助于保證合金的均勻性和穩(wěn)定性。Inadditiontothecrystalstructure,wealsoconducteddetailedobservationsonthephasecompositionandmicrostructureofCoCrFeNiMhighentropyalloythroughscanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM).TheresultsshowedthatthealloywasmainlycomposedofasingleFCCphase,andnoobvioussecondphaseprecipitationwasobserved.Thissingle-phasestructurehelpstoensuretheuniformityandstabilityofthealloy.為了更深入地理解CoCrFeNiM高熵合金的原子尺度結(jié)構(gòu)，我們采用了原子探針層析（APT）技術(shù)。APT技術(shù)能夠提供三維原子尺度的元素分布信息，對于揭示高熵合金中元素間的混合程度和原子間相互作用具有重要意義。通過APT分析，我們發(fā)現(xiàn)Co、Cr、Fe、Ni和M元素在合金中均勻分布，形成了典型的固溶體結(jié)構(gòu)。這種均勻的原子分布有利于合金性能的穩(wěn)定性和可靠性。InordertogainadeeperunderstandingoftheatomicscalestructureofCoCrFeNiMhighentropyalloys,weemployedatomicprobetomography(APT)technology.APTtechnologycanprovidethree-dimensionalatomicscaleelementdistributioninformation,whichisofgreatsignificanceforrevealingthedegreeofelementmixingandatomicinteractionsinhighentropyalloys.ThroughAPTanalysis,wefoundthatCo,Cr,Fe,Ni,andMelementsareuniformlydistributedinthealloy,formingatypicalsolidsolutionstructure.Thisuniformatomicdistributionisbeneficialforthestabilityandreliabilityofalloyproperties.CoCrFeNiM高熵合金的晶體結(jié)構(gòu)、相組成和原子尺度結(jié)構(gòu)都表明其具有良好的結(jié)構(gòu)穩(wěn)定性和均勻性。這些結(jié)構(gòu)特點為合金的優(yōu)異性能提供了堅實的基礎(chǔ)。未來，我們將繼續(xù)深入研究這種合金的性能優(yōu)化和應(yīng)用拓展。Thecrystalstructure,phasecomposition,andatomicscalestructureofCoCrFeNiMhighentropyalloyindicatethatithasgoodstructuralstabilityanduniformity.Thesestructuralcharacteristicsprovideasolidfoundationfortheexcellentperformanceofalloys.Inthefuture,wewillcontinuetoconductin-depthresearchontheperformanceoptimizationandapplicationexpansionofthisalloy.四、CoCrFeNiM高熵合金的性能PerformanceofCoCrFeNiMHighEntropyAlloyCoCrFeNiM高熵合金作為一種新型的金屬材料，具有優(yōu)異的力學(xué)性能和物理性能，使其在航空航天、能源、汽車等領(lǐng)域具有廣泛的應(yīng)用前景。本章節(jié)將詳細探討CoCrFeNiM高熵合金的各項性能表現(xiàn)。CoCrFeNiMhighentropyalloy,asanewtypeofmetalmaterial,hasexcellentmechanicalandphysicalproperties,makingitwidelyapplicableinaerospace,energy,automotiveandotherfields.ThischapterwillexploreindetailthevariousperformanceindicatorsofCoCrFeNiMhighentropyalloys.CoCrFeNiM高熵合金展現(xiàn)出良好的強度和塑性。通過拉伸測試，發(fā)現(xiàn)其具有較高的屈服強度和抗拉強度，同時延伸率也相對較高。這主要得益于合金中各組元之間的協(xié)同作用，以及合金化元素對基體金屬的強化作用。CoCrFeNiM高熵合金還具有較好的抗疲勞性能，可以承受較高的循環(huán)載荷而不發(fā)生破壞。CoCrFeNiMhighentropyalloyexhibitsgoodstrengthandplasticity.Throughtensiletesting,itwasfoundthatithashighyieldstrengthandtensilestrength,andrelativelyhighelongation.Thisismainlyduetothesynergisticeffectbetweenthevariouscomponentsinthealloy,aswellasthestrengtheningeffectofalloyingelementsonthematrixmetal.CoCrFeNiMhighentropyalloyalsohasgoodfatigueresistanceandcanwithstandhighcyclicloadswithoutfailure.CoCrFeNiM高熵合金的熱穩(wěn)定性較高，能夠在高溫環(huán)境下保持較好的性能。通過熱穩(wěn)定性測試，發(fā)現(xiàn)該合金在較高溫度下仍具有較高的硬度和強度，表現(xiàn)出良好的抗蠕變性能。該合金還具有較好的導(dǎo)電性和導(dǎo)熱性，可以滿足一些特定應(yīng)用場合的需求。TheCoCrFeNiMhighentropyalloyhashighthermalstabilityandcanmaintaingoodperformanceinhigh-temperatureenvironments.Throughthermalstabilitytesting,itwasfoundthatthealloystillhashighhardnessandstrengthathighertemperatures,exhibitinggoodcreepresistance.Thisalloyalsohasgoodconductivityandthermalconductivity,whichcanmeettheneedsofsomespecificapplicationscenarios.CoCrFeNiM高熵合金在多種腐蝕介質(zhì)中表現(xiàn)出良好的耐蝕性能。通過電化學(xué)腐蝕測試，發(fā)現(xiàn)該合金具有較低的腐蝕速率和較高的耐蝕電位，表明其具有較好的耐蝕性能。該合金還具有良好的抗氧化性能，可以在高溫氧化環(huán)境中保持較好的穩(wěn)定性。CoCrFeNiMhighentropyalloyexhibitsgoodcorrosionresistanceinvariouscorrosivemedia.Throughelectrochemicalcorrosiontesting,itwasfoundthatthealloyhasalowercorrosionrateandahighercorrosionresistancepotential,indicatingitsgoodcorrosionresistanceperformance.Thisalloyalsohasgoodoxidationresistanceandcanmaintaingoodstabilityinhigh-temperatureoxidationenvironments.CoCrFeNiM高熵合金具有較好的加工性能，可以通過鑄造、鍛造、軋制等工藝進行加工。在加工過程中，該合金具有較好的塑性和變形能力，可以得到較好的成品質(zhì)量和尺寸精度。該合金還具有較好的焊接性能，可以通過焊接等連接方式進行組合使用。CoCrFeNiMhighentropyalloyhasgoodprocessingperformanceandcanbeprocessedthroughprocessessuchascasting,forging,androlling.Duringtheprocessing,thisalloyhasgoodplasticityanddeformationability,andcanachievegoodfinishedproductqualityanddimensionalaccuracy.Thisalloyalsohasgoodweldingperformanceandcanbecombinedandusedthroughweldingandotherconnectionmethods.CoCrFeNiM高熵合金具有優(yōu)異的力學(xué)性能、物理性能、耐蝕性能和加工性能，是一種具有廣泛應(yīng)用前景的新型金屬材料。在未來的研究中，可以進一步探索該合金的制備工藝優(yōu)化、性能改進以及應(yīng)用領(lǐng)域拓展等方面的工作。CoCrFeNiMhighentropyalloyhasexcellentmechanical,physical,corrosionresistance,andprocessingproperties,makingitanewtypeofmetalmaterialwithbroadapplicationprospects.Infutureresearch,furtherexplorationcanbeconductedontheoptimizationofthepreparationprocess,performanceimprovement,andexpansionofapplicationareasofthisalloy.五、CoCrFeNiM高熵合金的應(yīng)用前景ApplicationprospectsofCoCrFeNiMhighentropyalloysCoCrFeNiM高熵合金作為一種新型的高性能金屬材料，在多個領(lǐng)域具有廣闊的應(yīng)用前景。其獨特的力學(xué)性能和耐腐蝕性使得它在航空航天、能源、汽車、生物醫(yī)學(xué)等領(lǐng)域具有巨大的潛力。CoCrFeNiMhighentropyalloy,asanewtypeofhigh-performancemetalmaterial,hasbroadapplicationprospectsinmultiplefields.Itsuniquemechanicalpropertiesandcorrosionresistancemakeithaveenormouspotentialinfieldssuchasaerospace,energy,automotive,biomedical,etc.在航空航天領(lǐng)域，CoCrFeNiM高熵合金的高強度、高硬度和良好的抗疲勞性能使其成為制造飛機和航天器關(guān)鍵部件的理想材料。其優(yōu)異的抗高溫氧化性能也使得它在高溫環(huán)境下具有良好的穩(wěn)定性，適用于制造高溫部件。Intheaerospacefield,thehighstrength,highhardness,andgoodfatigueresistanceofCoCrFeNiMhighentropyalloymakeitanidealmaterialformanufacturingkeycomponentsofaircraftandspacecraft.Itsexcellenthigh-temperatureoxidationresistancealsomakesithavegoodstabilityinhigh-temperatureenvironments,makingitsuitableformanufacturinghigh-temperaturecomponents.在能源領(lǐng)域，CoCrFeNiM高熵合金的耐腐蝕性使其成為制造海洋工程設(shè)備和太陽能設(shè)備的理想材料。特別是在海洋環(huán)境中，其優(yōu)良的耐腐蝕性能可以顯著延長設(shè)備的使用壽命。Intheenergyfield,thecorrosionresistanceofCoCrFeNiMhighentropyalloymakesitanidealmaterialformanufacturingmarineengineeringequipmentandsolarenergyequipment.Especiallyinmarineenvironments,itsexcellentcorrosionresistancecansignificantlyextendtheservicelifeofequipment.在汽車領(lǐng)域，隨著輕量化趨勢的不斷發(fā)展，CoCrFeNiM高熵合金的高強度和低密度使其成為制造汽車關(guān)鍵部件的優(yōu)質(zhì)材料。例如，它可以用于制造汽車的輪轂、支架等部件，以減輕汽車質(zhì)量，提高燃油效率。Intheautomotiveindustry,withthecontinuousdevelopmentoflightweighttrends,thehighstrengthandlowdensityofCoCrFeNiMhighentropyalloymakeitahigh-qualitymaterialformanufacturingkeyautomotivecomponents.Forexample,itcanbeusedtomanufacturecomponentssuchascarhubsandbracketstoreducecarweightandimprovefuelefficiency.在生物醫(yī)學(xué)領(lǐng)域，CoCrFeNiM高熵合金的生物相容性和耐腐蝕性使其成為制造醫(yī)療器械和植入物的理想材料。例如，它可以用于制造牙科植入物、人工關(guān)節(jié)等醫(yī)療器械，為患者的康復(fù)提供有力支持。Inthefieldofbiomedicalengineering,thebiocompatibilityandcorrosionresistanceofCoCrFeNiMhighentropyalloymakeitanidealmaterialformanufacturingmedicaldevicesandimplants.Forexample,itcanbeusedtomanufacturemedicaldevicessuchasdentalimplantsandartificialjoints,providingstrongsupportforpatientrehabilitation.CoCrFeNiM高熵合金憑借其優(yōu)異的力學(xué)性能和耐腐蝕性，在航空航天、能源、汽車、生物醫(yī)學(xué)等多個領(lǐng)域具有廣泛的應(yīng)用前景。隨著科技的不斷進步和材料的不斷優(yōu)化，相信CoCrFeNiM高熵合金將在未來發(fā)揮更加重要的作用。CoCrFeNiMhighentropyalloyhasbroadapplicationprospectsinvariousfieldssuchasaerospace,energy,automotive,biomedical,etc.duetoitsexcellentmechanicalpropertiesandcorrosionresistance.Withthecontinuousprogressoftechnologyandthecontinuousoptimizationofmaterials,itisbelievedthatCoCrFeNiMhighentropyalloyswillplayamoreimportantroleinthefuture.六、結(jié)論與展望ConclusionandOutlook經(jīng)過一系列的實驗與分析，本文系統(tǒng)地研究了CoCrFeNiM高熵合金的制備、結(jié)構(gòu)及其性能。通過真空熔煉法成功制備了CoCrFeNiM高熵合金，并通過RD、SEM、TEM等表征手段對其結(jié)構(gòu)進行了詳細分析。實驗結(jié)果表明，該高熵合金具有單一的FCC結(jié)構(gòu)，且元素分布均勻，無明顯偏析現(xiàn)象。該合金還展現(xiàn)出優(yōu)異的力學(xué)性能，如高強度、高硬度以及良好的延展性。Afteraseriesofexperimentsandanalysis,thispapersystematicallystudiedthepreparation,structure,andpropertiesofCoCrFeNiMhighentropyalloy.CoCrFeNiMhighentropyalloywassuccessfullypreparedbyvacuummeltingmethod,anditsstructurewasanalyzedindetailbycharacterizationmethodssuchasRD,SEM,andTEM.TheexperimentalresultsindicatethatthehighentropyalloyhasasingleFCCstructure,withuniformelementdistributionandnoobvioussegregationphenomenon.Thisalloyalsoexhibitsexcellentmechanicalproperties,suchashighstrength,highhardness,andgoodductility.在力學(xué)性能方面，CoCrFeNiM高熵合金的強度和硬度均超過了傳統(tǒng)的合金材料，這得益于其高熵效應(yīng)帶來的獨特組織結(jié)構(gòu)。同時，該合金還表現(xiàn)出良好的延展性，這為其在實際工程中的應(yīng)用提供了可能。Intermsofmechanicalproperties,thestrengthandhardnessofCoCrFeNiMhighentropyalloyexceedt